using System;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.GamerServices;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Input.Touch;
using Microsoft.Xna.Framework.Media;

namespace ChildrenOfWar
{
    /// <summary>
    /// This is the main type for your game
    /// </summary>
    public class COWGame : Microsoft.Xna.Framework.Game
    {
        internal GraphicsDeviceManager graphics;
        internal SpriteBatch spriteBatch;
        COWLevel level;//current level

        //Touch varibles. Notes where the last screen touch was and if the screen was touched during the lasy cycle.
        Vector2 oldTouchLoc;
        bool bScreenTouched;

        public COWGame()
        {
            graphics = new GraphicsDeviceManager(this);
            Content.RootDirectory = "Content";

            // Frame rate is 30 fps by default for Windows Phone.
            TargetElapsedTime = TimeSpan.FromTicks(333333);

            // Extend battery life under lock.
            InactiveSleepTime = TimeSpan.FromSeconds(1);
        }

        

        /// <summary>
        /// Allows the game to perform any initialization it needs to before starting to run.
        /// This is where it can query for any required services and load any non-graphic
        /// related content.  Calling base.Initialize will enumerate through any components
        /// and initialize them as well.
        /// </summary>
        protected override void Initialize()
        {
            //test logic, immediatly loads a level upon intialization
            level = COWLevelIO.LoadLevelASCII("content\\Level1.txt");//COWLevelIO.LoadLevel("content\\level.bin");
            level.Initalize(this);

            base.Initialize();
        }

        /// <summary>
        /// LoadContent will be called once per game and is the place to load
        /// all of your content.
        /// </summary>
        protected override void LoadContent()
        {
            // Create a new SpriteBatch, which can be used to draw textures.
            spriteBatch = new SpriteBatch(GraphicsDevice);
        }

        /// <summary>
        /// UnloadContent will be called once per game and is the place to unload
        /// all content.
        /// </summary>
        protected override void UnloadContent()
        {
        }

        /// <summary>
        /// Allows the game to run logic such as updating the world,
        /// checking for collisions, gathering input, and playing audio.
        /// </summary>
        /// <param name="gameTime">Provides a snapshot of timing values.</param>
        protected override void Update(GameTime gameTime)
        {
            // Allows the game to exit
            if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
                this.Exit();

            //If the screen is touched, record the vector of the touch location. If it was touched during the last update (bScreenTouched is already true) 
            //then move the camera the difference between this touch and the last touch. Then update the old touch location and note that the screen was touched.
            //Otherwise, simply note that the screen was not touched.
            if (Mouse.GetState().LeftButton == ButtonState.Pressed)
            {
                Vector2 TouchLoc = new Vector2(Mouse.GetState().X, Mouse.GetState().Y);
                if(bScreenTouched)
                {
                    level.MoveCamera(oldTouchLoc - TouchLoc);
                }
                bScreenTouched = true;
                oldTouchLoc = TouchLoc;
            }
            else
            {
                bScreenTouched = false;
            }
            base.Update(gameTime);
        }

        /// <summary>
        /// This is called when the game should draw itself.
        /// </summary>
        /// <param name="gameTime">Provides a snapshot of timing values.</param>
        protected override void Draw(GameTime gameTime)
        {
            GraphicsDevice.Clear(Color.White);

            //If a level exists, draw it.
            if (level != null)
            {
                level.draw();
            }
            base.Draw(gameTime);
        }
    }
}
